System for analysis of body fluids and wound-associated biomolecules

Abstract

A system for analyzing a wound fluid. The system includes a transparent layer, a membrane layer, and an indicator layer that contains a colorimetric or fluorescent indicator reagent for detecting pH, a nitrite, an enzyme, a reactive oxygen species, a reactive nitrogen species, a nucleic acid, or a combination thereof. The membrane layer is impermeable to blood clots and cellular debris and is permeable to wound fluid. Also provided are methods for analyzing a wound fluid and for detecting biological fluid on biomedical instruments and waste materials using the system.

What is claimed is: 
     
       1. A system for analyzing a wound fluid, the system comprising a non-porous waterproof base layer, a transparent layer, an indicator layer, and a membrane layer, the indicator layer containing a colorimetric or fluorescent indicator reagent for detecting one or more of pH, a nitrite, a protease, an esterase, a reactive oxygen species, a reactive nitrogen species, and a nucleic acid, wherein the membrane layer is impermeable to blood clots and cellular debris and is permeable to wound fluid, the indicator layer is located in between the transparent layer and the membrane layer, the colorimetric or fluorescent indicator reagent is present throughout the indicator layer in an amount of 1 ng/cm 2  to 1 g/cm 2 , the transparent layer, being non-porous, is clear such that a color change of the colorimetric or fluorescent indicator reagent can be visualized through the transparent layer, and the base layer, the membrane layer, and the transparent layer are joined together along a single edge, the base layer for preventing liquid from leaking out of the system during use. 
     
     
       2. The system of  claim 1 , wherein the membrane layer is 5 μm to 1.0 mm thick and has a pore size of 5 nm to 50 μm. 
     
     
       3. The system of  claim 2 , wherein the membrane layer is 0.1 mm to 0.6 mm thick and has a pore size of 5 μm to 50 μm. 
     
     
       4. The system of  claim 1 , wherein the colorimetric or fluorescent indicator reagent is present in the indicator layer in an amount of 1 μg/cm 2  to 1 mg/cm 2 . 
     
     
       5. The system of  claim 1 , wherein the membrane layer is formed of one or more of cellulose, nitrocellulose, methyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, hydroxypropyl methylcellulose, ethyl hydroxyethyl cellulose, carboxymethyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cellulose nitrate nylon, nylon, viscose, cotton, rayon, wool, silk, (poly) hydroxyethyl methacrylate, (poly) hydroxypropyl methacrylate, (poly) glycerol methacrylate, copolymers of hydroxyethyl methacrylate, hydroxypropyl methacrylate, or glycerol methacrylate and methacrylic acid, aminoacrylate and amino methacrylate, (poly) vinylpyridine, polyvinyl acetate, polyvinyl alcohol, copolymers of poly 4-vinylacetate and polyvinyl alcohol, hydroxyl modified copolymers of vinyl acetate and vinyl chloride, polyesters and polyurethanes containing at least 10% by weight polyethylene oxide, styrene, methacrylic acid/hydroxyethyl methacrylate copolymers, methyl methacrylate/methacrylic acid copolymers, ethyl methacrylate/styrene/methacrylic acid copolymers, ethyl methacrylate/methyl methacrylate/styrene/methacrylic acid copolymers, or polytetrafluoroethylene. 
     
     
       6. The system of  claim 5 , wherein the membrane layer is formed of cellulose, nitrocellulose, or nylon. 
     
     
       7. The system of  claim 6 , wherein the membrane layer is 5 μm to 1.0 mm thick and has a pore size of 5 nm to 50 μm. 
     
     
       8. The system of  claim 7 , wherein the colorimetric or fluorescent indicator reagent for detecting pH is selected from the group consisting of nitrazine yellow, bromocresol green, chlorophenol red, bromothymol blue, phenol red, thymol blue, methyl red, methyl orange, methyl yellow, propyl red, litmus, phenolphthalein, and a sulfonephthalein indicator. 
     
     
       9. A method for analyzing a wound fluid, the method comprising:
 obtaining a system of  claim 1  that includes a transparent layer, an indicator layer, and a membrane layer having a first surface and a second surface opposed to the first surface, the indicator layer being located between the transparent layer and the second surface, 
 obtaining a wound dressing that is impregnated with a wound exudate, 
 covering the wound dressing with the membrane layer such that the first surface of the membrane layer is in contact with the wound dressing, 
 contacting the indicator layer with the second surface of the membrane layer, 
 incubating the wound dressing with the system such that the wound exudate transfers through the membrane layer to the indicator layer and components of the wound exudate react with the colorimetric or fluorescent indicator reagent, and 
 visualizing one or more color changes in the indicator layer through the transparent layer, 
 
       wherein the one or more color changes in the indicator layer are each present at a location corresponding to the location in the wound dressing of the components of the wound exudate that reacted with the colorimetric or fluorescent indicator reagent. 
     
     
       10. The method of  claim 9 , further comprising hydrating the wound dressing with a salt solution having a pH of 5-11 and a concentration of 1-6 M. 
     
     
       11. The method of  claim 10 , wherein the salt solution contains NaCl, KCl, KI, KH 2 PO 4 , K 2 HPO 4 , or tris(hydroxymethyl)aminomethane. 
     
     
       12. The method of  claim 11 , wherein the hydrating step is accomplished by applying the salt solution to the wound dressing prior to the placing step. 
     
     
       13. The method of  claim 11 , wherein the hydrating step is accomplished by applying the salt solution to the first surface of the membrane prior to the covering step. 
     
     
       14. The method of  claim 11 , wherein the system further comprises a non-porous base layer and an edge of each of the transparent layer, the membrane layer, and the base layer are joined together. 
     
     
       15. The method of  claim 14 , wherein the indicator layer is integral with the transparent layer and does not extend to the edge of the transparent layer. 
     
     
       16. A method for detecting biological fluid on biomedical instruments and waste materials, the method comprising:
 obtaining a system of  claim 1  that includes a transparent layer, an indicator layer, and a membrane layer having a first surface and a second surface opposed to the first surface, the indicator layer being located between the transparent layer and the second surface, 
 obtaining a biomedical instrument or waste material that has been in contact with a biological fluid, 
 covering the biomedical instrument or waste material with the membrane layer such that the first surface of the membrane layer is in contact with the biomedical instrument or waste material, 
 contacting the indicator layer with the second surface of the membrane layer, 
 incubating the biomedical instrument or waste material with the system such that the biological fluid transfers through the membrane layer to the indicator layer and reacts with the colorimetric or fluorescent indicator reagent, and 
 visualizing one or more color changes in the indicator layer through the transparent layer, 
 
       wherein the one or more color changes in the indicator layer are each present at a location that came into contact with a component of the biological fluid present on the biomedical instrument or waste material and reacted with the colorimetric or fluorescent indicator reagent. 
     
     
       17. The method of  claim 16 , wherein the system further comprises a non-porous base layer and an edge of each of the transparent layer, the membrane layer, and the base layer are joined together.